UNIT 1 Reading

INTRODUCTION TO COMPUTERS AND ELECTRONIC DATA

1. Computers have had a great

effect on modern society and have caused a great many changes in a short time. It is sometimes difficult to believe that computers firs came into existence during the late 1930 and that during this time, they were used mainly for scientific research in governmentand universities. Computer technology has developed very quickly and has greatlyinfluenced modern life .In fact, by the 1970s computers were used for applicationsthat were previously unthinkable. By the 1970s computer were common not onlyin business, which found them very helpful for all kinds of office tasks, but alsoin many other places, including retail stores, supermarkets, schools, and libraries.By the beginning of the 1980s computers could be found everywhere-in gasstations, in cars or in household appliances such as dishwashers or microwaveovens, just to name a few examples. In fact, by this time, microcomputers, orpersonal computers relatively small and inexpensive computers were becomingeven more common in both business and the home. Since the interest incomputers is increasing every day , and because tremendous advances arebeing made so quickly in computer technology, it is often difficult to envisionthe impact that computers will have in the future.COMPUTER TERMINOLOGY 2. Computers have brought about many changes in language, both in the United States and other countries. With the invention and use of the computer, an entire new vocabulary has developed words which describe the computer and itsfunctions, or relate to computer technology in some way. Such words includesoftware, the term used to refer to computer programs. programs are theinstructions that tell the computer what to do. Software is generally contrastedwith hardware, the actual physical parts of the computer system . Debug isanother term that came into existence with computers it means to locate andremove all mistakes in a computer program.3.Other computer-related words are not really new, but take on a specialmeaning in terms of computers . For example, up and down used in referenceto computers do not signify spatial relationships. Instead the term up meansthat the computer is up and working, while the term down means the oppositethat the computer is not functioning and cannot be used. Another example of aword which takes a special meaning in reference to computers is the word boot.When used to refer to computers , boot is not used to mean a kind of shoe. 4.Rather, boot is generally used as a verb. To boot a computer means to start itup. Other influences in language brought about by computer technology involvewords which have become almost exclusively associated with computers.Although they retain their original meaning . One such word is user. While userreally signifies one who uses something. Today it very often refers to a personusing a computer. Associated with the word user is the term user friendly .This is currently a very popular expression meaning that the computer can beeasily understood and operated by non-technical, non- computer people.WHAT IS A DATA PROCESSING? 5.In spite of the tremendous impact computers have made and will continue to make on society, many people do not really understand what a computer is or how it works. In fact most people may not know much about computers except that using them usually makes their lives easier.6.In very simple terms, a computer regardless of its size, appearance or cost , is amachine that process data facts- electronically. (data is the plural of datum;however, in common usage, the word data is often used in the singular).Processing data with a computer is relatively new; however , the idea ofprocessing data is not . In general , data processing (DP) can be defined as aseries of three steps:1) collection or gathering of data. 2) The manipulation or handling of data ,3) thedistribution or sending out of data or information for a particular purpose.Electronic data processing (EDP), therefore, is the collection, manipulation anddistribution of facts by electronic mean.-by computer. EDP has become the majormethod of processing data in modern society. In fact ; it is so common that thegeneral term data processing and the specific idea of electronic data processinghave become synonymous and are now used interchangeably.THE DATA PROCESSING CYCLE : INPUT, PROCESSING , OUTPUT 7. The data processing cycle takes place in three steps. First, data are put into a computer in a form the computer can understand. Second, the data are processed according to the instructions the computer receives throughprograms. Third, the data now in a form understandable and meaningful to people,come out.DATA VERSUS INFORMATION 8. We have already mentioned that facts which are put into the computer are called data. Data are raw facts or figures which are arranged in such a way that the computer can accept and process them.When data are put into or input into, the computer they may not n bemeaningful by themselves. Once the data have been handle or processed by thecomputer they are changed into useful information. This useful informationthen comes out from or is output by the computer so that people can use it.This is the purpose of the computer, and of data processing to process data sothat they become useful information.THE FORM OF DATE 9.In order for data to be processed by a computer , they must be machine readable that is , expressed in a form the computer understands. Computers cannot deal with emotions, opinions, orfeelings. All computer information is expressed by a numeric code. The computertransform everything letters of the alphabet, numbers, punctuation marks, sounds,special symbols, etc. into its own number system so that the data can beprocessed.

ORGANIZATION OF DATA 10. Data for a computer can be organized in several different ways. One unit of data is called a field. An example of a field may be a persons name. Several individuals fields, such as a field for an individuals name, a field for nationality, and a field for the language a particular student speaks, can be combined together to form a record. A record therefore, is a group of fields related to a particular unit of information. Records, like, fields can be combined together into arelated group. A group of related records is called file. A student information filemay consist of individual records, each containing a name, nationality andlanguage field. Data can also be organized into very large collections called databases. Each data base is a collection of related items which is organized so that itcan be used for different purposes. For example , a data base containinginformation about an individual students name, nationality, and language , likethe one described above , could be used both to determine the number ofstudents from a particular country and to classify students according to thelanguage each individual speaks.CHARACTERISTICS OF COMPUTERS: ACCURACY AND SPEED

11. Computers not only process data, they

process data very accurately. Data are processed by the computer by being transmitted electronically through the computers circuits. Since electronic circuits rarely fail, the computer is almost always 100% correct. When a mistake is made it may not really be the computers fault. Theproblem is usually due to human error, either to a mistake in the computer programor to a mistake in the data input into the computer. In fact, There is a special term, an acronym to indicate that if badly organized or incorrect data are input intothe computer , the information that is output will be meaningless. This termGIGO, stands for garbage, in garbage out and emphasizes the importance of usingaccurate data when dealing with computers.12. Besides accuracy, speed is another characteristic of a computer. All computerfunctions are carried out in a very small units of time which are almostimpossible for people to imagine. Two of these units are microseconds andnanoseconds. A microsecond is one thousand (1/ 1,000) of a second, while ananosecond is one-billionth (1/1,000,000,000) of a second. The speed of acomputer is measured in these units and is calculated by the time it takes tocomplete a particular job, such as adding numbers. A few smaller computersmay need microseconds to complete a job while other , perhaps largercomputers, work much faster and need only nanoseconds , in the near futurecomputer speed may be measured in psico-seconds equal to one trillionth (1/1,000,000,000,000) of a second.The speed of a computer is measured in these units and is calculated by the timeit takes to complete a particular job, such as adding numbers. A few smallercomputers may need microseconds to complete a job while other, perhaps largercomputers, work much faster and need only nanoseconds to do the same thing.While many computers currently measure speed in nanoseconds, in the nearfuture computer speed may be measured in psicoseconds, equal to one trillionth(1/1,000,000,000,000) of a second.

PROGRAMS 13. While computers process data very accurately and very quickly, they cannot think themselves. In order for computers to function, they must receive instructions that control the input and processing of data, as well as the output of information. A Computer program also called a stored program, is a specific set of instructions that tells the computer what to do. Programs are not part of acomputer, they are separate. Therefore, programs must be put into the computeralong with data, in order for processing to take place. Programs, or software, canbe written in many different computer languages.COMPUTER OPERATIONS

14. We have already stated that all types

of computers, small personal computers or large computers, work the same way and have the same basic cycle input, processing, output. All computers are also capable of performing a small number of operations. These operations can be divided into three basic types: input andoutput operations (accepting facts and giving out information); arithmeticoperations (adding, subtracting, multiplying and dividing numbers); and logicaloperations (comparing numbers). These will be discussed further in connectionwith the computer system. With only these three types of operations, computerscan accurately and quickly perform six major functions: storing, calculating,comparing, classifying, storing and summarizing.

THE COMPUTER SYSTEM

15. All the functions of the computer are carried out by the computer system. All computer system consists of three basic parts: input units, a processor unit, and output units Input units accept both the data and the programs needed for processing, and present them to the processor unit, Output units display the results obtainedfrom processing The processor unit, which both stores and process data, has twomain parts: the central processing unit (CPU), and the main storage unit Inaddition, most computers also have some kind of auxiliary, or extra, storage. In summary, computers are devices that process data quickly and accurately Regardless of size, cost orappearance all computers have the same basic cycle, are made up of the samebasic parts, and perform the same types of operations. In spite of all theircapabilities, however, computers need direction form people. Directed by humancreativity and imagination, the use of computers will continue to develop, makingthese machines even more valuable in the future.